fixed bug breaking longestCommonSubstring if first arg shorter than s…

…econd, fixes vkostyukov#27
longshorej · Nov 21, 2016 · 59fc41d · 59fc41d
1 parent 5898ecd
commit 59fc41d
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/src/primitive/Strings.scala b/src/primitive/Strings.scala
@@ -57,7 +57,11 @@ object Strings {
    * Time - O(mn)
    * Space - O(mn)
    */
-  def longestCommonSubstring(a: String, b: String) : String = {
+  def longestCommonSubstring(one: String, two: String) : String = {
+    val (a, b) =
+      if (one.length <= two.length) (one, two)
+      else (two, one)
+
     def loop(m: Map[(Int, Int), Int], bestIndices: List[Int], i: Int, j: Int) : String = {
       if (i > a.length) {
         b.substring(bestIndices(1) - m((bestIndices(0),bestIndices(1))), bestIndices(1))